Dry Creek Stream Watch

Macroinvertebrate testing rates Dry Creek as “Highly Impaired.”

In the fall of 2007, the Dry Creek Streamkeepers conducted macroinvertebrate sampling at Dry 0.8 near Kacee Way. The purpose of the testing was to sample benthic macroinvertebrates (underwater bugs) to determine the health of our stream. The type and number of underwater bugs can provide a health assessment of a stream. The method used to calculate the assessment is call the Benthic Index of Biological Integrity or B-IBI.

There were delays in having the 2007 samples professionally identified and the final results became available just this week. The B-IBI score was 20 which is a rating of “Highly Impaired.” The definition of Highly Impaired states there is “substantial loss of once-native life-forms, with taxa richness reduced by half. Highly adverse conditions for salmon.” This rating brings up the question of how an area basically isolated from housing and industry can decline to “Highly Impaired”???

The DCC has long held the belief that the Airport rerouting of Dry Creek in the 1990’s severly impacted downstream areas. Since Dry site 0.8 is 1/4 mile downstream of the reroute area, the test results clearly show the impact. It is also interesting to note that the our monitoring site above the Airport reroute area at Dry 2.2 was tested in 2006 and the score was 44 with a “Compromised” rating (typical for most streams in Clallam County). With this latest biologically impaired rating at Dry 0.8, we have established one of several steps to put Dry Creek on the States Dept of Ecology Impaired Water (303d) List.